Nuclear Magnetic Resonance can be used to study the properties of a fluid saturated rock sample. Using a magnetic field the tool aligns the spin of all protons in the pore fluid, the time to return to a random orientation (T2) is an indication of the both the fluid and its interaction with the rock sample.

Relative permeability is a suit of tests that attempt to model how a producing formation will behave over time, there are many different methods to determine relative permeability with many factor contributing to the final understanding of the system and these may include.